The present invention relates to a fuel tank of a straddle-type, so-called horse-back-riding-type, vehicle such as buggy car, which is provided with an improved air guide structure.
A straddle-type vehicle generally has a body frame, at its upper portion, covered by a body cover. An engine is disposed at a lower central portion of the body frame, and a fuel tank is arranged above the engine and inside the frame cover at an upper forward portion of the body cover. A straddle-type driver's seat is disposed behind the fuel tank. An air-cleaner is also disposed below the driver's seat on the rear side of the engine.
At a time, when the straddle-type vehicle runs, for example, on a river side road, mud or water is splashed during the running. In such arrangement of the vehicle, therefore, an intake port of the air cleaner is designed so as to be disposed at an upper side inside the body frame, i.e., as below the driver's seat to prevent mud or water splashed during the running from invading into the air cleaner through the intake port.
However, in the arrangement in which the intake port of the air cleaner is positioned below the driver's seat, an intake noise generated at a gap between the fuel tank and the driver's seat will give uncomfortable feeling to a driver. Moreover, because of the arrangement that the outer periphery of the intake port is surrounded by the engine, the body cover, etc., intake resistance against the taken air is increased, and because of high temperature of the taken air, output performance of the engine will be deteriorated.
On the other hand, in the structure of a water-cooled type engine, a radiator is often arranged in front of the engine, and in such arrangement, smooth running flow (air-flow caused by the running of a vehicle) will be blocked by the radiator, which results in an increasing of a temperature of the atmosphere surrounding the engine.